.gamma.-correction curve selecting apparatus and a .gamma.-correction curve creating apparatus

- Ricoh Company, Ltd.

An image processing apparatus capable of creating or selecting a most suitable .gamma.-correction curve and shortening the image quality adjusting time. According to the invention, in an image processing apparatus for correcting the .gamma.-characteristic of the density value for each pixel of the original image to be processed and the output value of the image processing measure in the predetermined apparatus for receiving the image, or the .gamma.-characteristic of the writing-in value of the image processing apparatus in the predetermined apparatus for outputting the image and the density of the output image, the image processing apparatus includes a .gamma.-correction curve creating device for creating the .gamma.-correction curve from the input .gamma.-characteristic, and a second .gamma.-correction curve selecting device for selecting the most suitable .gamma.-correction curve among the plural .gamma.-correction curves by use of the .gamma.-correction curve emitted from the .gamma.-correction curve creating device.

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Claims

1. An image processing apparatus comprising: dither-processing means and a multi-value outputting apparatus for receiving the output signal of said dither-processing means and outputting at least two values which correct the first.gamma.-characteristic of the writing-in value to be input to said dither-processing means of said image processing apparatus and the output image of said multi-value outputting apparatus; and

a.gamma.-correction curve creating apparatus including.gamma.-characteristic curve creating means for creating said first.gamma.-characteristic from the second.gamma.-characteristic of the input signal of said multi-value outputting apparatus and the output image thereof, and a.gamma.-correction curve creating portion for creating a most suitable.gamma.-correction curve from the output of said.gamma.-characteristic curve creating means.

2. An image processing apparatus comprising at least two types of dither-processing means, dither-processing selection means for changing between said at least two types of dither-processing means, and a multi-value outputting apparatus for receiving the output signal of said dither-processing selection means and outputting two or more values which correct the first.gamma.-characteristic of the writing-in value to be input to said dither-processing means of said image processing apparatus and the output image of said multi-value outputting apparatus; and

a.gamma.-correction curve creating apparatus of said image processing apparatus including.gamma.-characteristic curve creating means for creating two or more types of said first.gamma.-characteristic from the second.gamma.-characteristic of the input signal of said multi-value outputting apparatus and the output image thereof,.gamma.-characteristic selecting means for selecting two or more types of said first.gamma.-characteristic from said.gamma.-characteristic curve creating means in accordance with the selection signal of said dither-processing selection means, and.gamma.-correction curve creating means for creating the.gamma.-correction curve from the.gamma.-characteristic emitted from said.gamma.-characteristic selecting means.

3. An image processing apparatus comprising at least two or more types of dither-processing means, dither-processing selection means for changing between said at least two or more types of dither-processing means, and a multi-value outputting apparatus for receiving the output signal of said dither-processing selection means and outputting two or more values which correct the first.gamma.-characteristic of the writing-in value to be input to said dither-processing means of said image processing apparatus and the output image of said multi-value outputting apparatus; and

a.gamma.-correction curve creating apparatus including.gamma.-characteristic curve creating means for creating said first.gamma.-characteristic from the second.gamma.-characteristic of the input signal of said multi-value outputting apparatus and the output image thereof in accordance with the selection signal of said dither-processing selection means.

4. The.gamma.-correction curve creating apparatus according to one of claims 1 and 2, wherein said.gamma.-correction curve creating apparatus is constructed with approximation means for approximating the.gamma.-characteristic curve using a functional approximation method.

5. The.gamma.-correction curve creating apparatus according to one of claims 1 and 2, said.gamma.-correction curve creating apparatus includes a neural network previously studying the.gamma.-correction curve.

Referenced Cited
U.S. Patent Documents
4792979 December 20, 1988 Nomura et al.
5216463 June 1, 1993 Morita
5296919 March 22, 1994 Maruno et al.
5353239 October 4, 1994 Kashiwagi
5363318 November 8, 1994 McCauley
5376962 December 27, 1994 Zortea
Patent History
Patent number: 5712930
Type: Grant
Filed: Dec 30, 1996
Date of Patent: Jan 27, 1998
Assignee: Ricoh Company, Ltd. (Tokyo)
Inventor: Hideyuki Watanabe (Kawasaki)
Primary Examiner: Scott A. Rogers
Law Firm: Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Application Number: 8/774,642
Classifications
Current U.S. Class: Variable Threshold, Gain, Or Slice Level (382/270); Intensity, Brightness, Contrast, Or Shading Correction (382/274); 358/457; 358/458
International Classification: H04N 140; H04N 1403;